Grey talon activating arcane surge does not increase the damage of charged shot ability

[Mastou]

When activating arcane surge and hitting a target with charged shot ability. It shows the same damage value as if you would not have activated arcane surge.

It would seem that after grey talon releases his Charged Shot ability, the ability power Arcane Surge provides drops to the base spirit power you had before activating it. Which makes me think it is the reason the damage isn't increased for the ability.